1. Technical Field
The present invention relates to a stripping apparatus for stripping a metal film from a metallized plastic film.
A metallized plastic film for a condensor is prepared by vacuum vapor deposition of a metal film, such as aluminum, onto one side of an extremely thin plastic film. In a condensor using such a metallized plastic film, when wound the cut ends of metal film wound one upon another often contact to cause a short-circuit. In order to prevent such a short-circuit it is necessary to partially strip the deposited metal film from the plastic film. In such a metallized plastic film, the beginning part of the winding is stripped and also, as shown in FIG. 1, a fixed length of metal film at regular intervals is stripped according to volume and pressure conditions (in the FIGURE, 01 is a metal film and 02 shows a stripped part).
2. DISCUSSION OF THE BACKGROUND
The prior stripping apparatus for stripping a metal film is, as shown in FIG. 2, constituted by providing electricity supplying rollers 4 and 5 between roll I and winding roll 2 on the metal film side of a metallized plastic film 3. Further, winding rolls 7 and 9 are provided for winding aluminum foil through the supplying rollers 4 and 5, respectively, with rolls 6 and 8 feeding aluminum foil and connecting supplying rollers 4 and 5 to a cathode (or anode) and an anode (or cathode), respectively.
When contacting supplying rollers 4 and 5 with the metallized plastic film 3 running from roll 1 to winding roll 2, and charging the cathode voltage (or anode voltage) and anode voltage (or cathode voltage) to the supplying rollers 4 and 5, respectively, only for a period of charging, the metal of the metal film is liquefied due to the current load. As a result, the vacuum vapor deposited face between the plastic film and the metal film is broken due to the elevated temperature, such that the metal film is stripped. The stripped metal film is transferred onto an aluminum foil on the supplying roller 5 to be wound upon winding roll 9.
The prior apparatus must be large in scale as a result of the equipment required for the stripping apparatus. In addition, the aluminum foils transferring the metal film thereon and wound upon the roll 9 and onto the roll 7 through the supplying roller 4 can only be scrapped and therefore are a large burden on the cost in the winding step. Further, there are many problems in that the remnants of stripped metal film accumulate at a point of contact of the supplying roller with the plastic film, as shown in FIG. 3.